ABSTRACT: Patient-derived xenografts of HER2-positive breast cancer brain metastases facilitate discovery of a therapeutic strategy yielding durable remissions
Project description:Patient-derived xenografts of HER2-positive breast cancer brain metastases facilitate discovery of a therapeutic strategy yielding durable remissions
Project description:Breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. To overcome these limitations, we propagated a cohort of human breast tumors grown in the epithelium-free mammary fat pad of SCID/Beige and NOD/SCID/IL2γ-receptor null (NSG) mice, under a series of transplant conditions. Both models yielded stably transplantable xenografts at comparably high rates (~23% and ~19%, respectively). Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 32 stably transplantable xenograft lines were established, representing unique 25 patients. Most tumors yielding xenografts were “triple-negative” (ER-PR-HER2+) (n=19). However, we established lines from three ER-PR-HER2+ tumors, one ER+PR-HER2-, one ER+PR+HER2- and one “triple-positive” (ER+PR+HER2+) tumor. Serially passaged xenografts show biological consistency with the tumor of origin, are phenotypic stability across multiple transplant generations at the histological, transcriptomic, proteomic, and genomic levels, and show comparable treatment responses. Xenografts representing 12 patients, including two ER+ lines, showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource for preclinical studies investigating treatment response and metastasis. The study was designed to determine how stable patient-derived xenografts are across multiple transplant generations in mice, and to determine how closely xenografts established with pre-treatment samples cluster with xenografts established with post-treatment samples. Overall, pre-treatment and post-treatment samples derived from the same patient cluster together, and multiple transplant generations of xenografts derived from an individual patient cluster together.
Project description:Breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. To overcome these limitations, we propagated a cohort of human breast tumors grown in the epithelium-free mammary fat pad of SCID/Beige and NOD/SCID/IL2γ-receptor null (NSG) mice, under a series of transplant conditions. Both models yielded stably transplantable xenografts at comparably high rates (~23% and ~19%, respectively). Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 32 stably transplantable xenograft lines were established, representing unique 25 patients. Most tumors yielding xenografts were “triple-negative” (ER-PR-HER2+) (n=19). However, we established lines from three ER-PR-HER2+ tumors, one ER+PR-HER2-, one ER+PR+HER2- and one “triple-positive” (ER+PR+HER2+) tumor. Serially passaged xenografts show biological consistency with the tumor of origin, are phenotypic stability across multiple transplant generations at the histological, transcriptomic, proteomic, and genomic levels, and show comparable treatment responses. Xenografts representing 12 patients, including two ER+ lines, showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource for preclinical studies investigating treatment response and metastasis.
Project description:Translational breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. In an effort to overcome these limitations, we propagated a cohort of human breast tumors grown in the mammary fat pad of SCID/Beige and NOD/SCID/IL2?-receptor null (NSG) two relatively new immunocompromised mouse models, under a series of transplant conditions. Both models yielded stably transplantable xenografts relatively high rates compared with previously available immunocompromised mice. Xenograft lines were established directly from breast cancer patient samples, without intervening culture in vitro, using the epithelium-free mammary fat pad as the transplantation site. Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 35 stably transplantable xenograft lines representing 27 patients were established, using pre-treatment, mid-treatment, and/or post-treatment samples. Most patients yielding xenografts were “triple-negative” (ER-PR-HER2-) (n=21). However, we were able to establish lines from three ER-PR-HER2+ patients, one ER+PR-HER2-, one ER+PR+HER2- and one “triple-positive” (ER+PR+HER2+) patient. Serially passaged xenografts show biological consistency with the tumor of origin at the histopathology level, and remarkable stability across multiple transplant generations at the genomic, transcriptomic, and proteomic levels. Of the 27 patients represented, xenografts derived from 13 patients showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource, and should prove useful for preclinical evaluation of experimental therapeutics. reference x sample
Project description:Combined targeting CDK4/6 and HER2 signaling in orthotopic patient-derived xenografts of HER2-positive breast cancer brain metastases
Project description:Combined targeting CDK4/6 and HER2 signaling in orthotopic patient-derived xenografts of HER2-positive breast cancer brain metastases
Project description:A human HER2-positive leptomeningeal colonization model, JIMT1-BR3-LM4, was established by intrathecal injection of the JIMT1-BR3 HER2+ cell line, which already formed parenchymal brain metastases and occasional leptomeningeal metastases. In this study, bulk RNA sequencing was performed to define transcriptomic differences between parental JIMT1-BR3 cells and the leptomeningeal-tropic derivative JIMT1-BR3-LM4. These data provide a resource for identifying gene expression changes associated with HER2-positive breast cancer leptomeningeal colonization.
Project description:Translational breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. In an effort to overcome these limitations, we propagated a cohort of human breast tumors grown in the mammary fat pad of SCID/Beige and NOD/SCID/IL2?-receptor null (NSG) two relatively new immunocompromised mouse models, under a series of transplant conditions. Both models yielded stably transplantable xenografts relatively high rates compared with previously available immunocompromised mice. Xenograft lines were established directly from breast cancer patient samples, without intervening culture in vitro, using the epithelium-free mammary fat pad as the transplantation site. Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 35 stably transplantable xenograft lines representing 27 patients were established, using pre-treatment, mid-treatment, and/or post-treatment samples. Most patients yielding xenografts were “triple-negative” (ER-PR-HER2-) (n=21). However, we were able to establish lines from three ER-PR-HER2+ patients, one ER+PR-HER2-, one ER+PR+HER2- and one “triple-positive” (ER+PR+HER2+) patient. Serially passaged xenografts show biological consistency with the tumor of origin at the histopathology level, and remarkable stability across multiple transplant generations at the genomic, transcriptomic, and proteomic levels. Of the 27 patients represented, xenografts derived from 13 patients showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource, and should prove useful for preclinical evaluation of experimental therapeutics.
Project description:Background: Central nervous system (CNS) metastases represent a major problem in the treatment of HER2-positive breast cancer due to the disappointing efficacy of HER2-targeted therapies in the brain microenvironment. The antibody-drug conjugate ado-trastuzumab emtansine (T-DM1) has shown efficacy in trastuzumab-resistant systemic breast cancer. Here, we tested the hypothesis that T-DM1 could overcome trastuzumab resistance in preclinical models of brain metastases. Methods: We treated mice bearing BT474 or MDA-MB-361 tumors in the CNS (N=9-11 per group), or cancer cells grown in organotypic brain slice cultures with trastuzumab or T-DM1 at equivalent or equipotent doses. Using intravital imaging, molecular techniques and histological analysis we determined tumor growth, mouse survival, cancer cell apoptosis and proliferation, tumor drug distribution, and HER2 signaling. All statistical tests were two-sided. Results: T-DM1 significantly delayed the growth of HER2-positive breast cancer brain metastases compared to trastuzumab. These findings were consistent between HER2-driven and PI3K-driven tumors. The activity of T-DM1 resulted in a striking survival benefit (median survival for BT474 tumors: 28d for trastuzumab vs 112d for T-DM1, HR=6.2, 95% CI=6.1 to 85.84; P<.001). No difference in drug distribution and HER2-signaling was revealed between the two groups. However, T-DM1 led to a significant increase in tumor cell apoptosis (One-way ANOVA for ApopTag, p<.001), which was associated with mitotic catastrophe. Conclusions: T-DM1 can overcome resistance to trastuzumab therapy in HER2-driven and PI3K-driven breast cancer brain lesions due to the cytotoxicity of the DM1 component. Clinical investigation of T-DM1 for patients with CNS metastases from HER2-positive breast cancer is warranted. Comparison of trastuzumab (n=4) and TDM-1 (n=4) treated BT-474 human breast carcinoma cells growing in murine brain
Project description:<p>We have developed orthotopic patient-derived xenograft models of HER2 positive breast cancer metastasized into the brain of patients to test novel therapeutic strategies. In this study, we identified a novel combinatorial therapeutic strategy that has resulted in a durable remission and markedly increased overall survival in majority of patient-derived xenograft (PDX) models tested. We performed whole exome sequencing analysis of these PDX tumors and their matched blood and patient samples to investigate drug sensitive and resistance mechanisms. Our sequencing data revealed an interesting association of genotyping and phenotyping with tumors responses to drug treatment.</p>